Angiotensin II activates Na+-H+ exchange and stimulates growth in cultured vascular smooth muscle cells

Angiotensin II (Ang II) stimulated the growth of cultured vascular smooth muscle cells in a dose-dependent manner; a small but significant increase being seen at 10(-9) mol/l, whereas 10(-5) mol/l produced a 166% increase compared with control cells. Saralasin blocked the Ang II-mediated increase in cell number. Amiloride-sensitive Na+-H+ exchange was characterized (Km = 18 mmol/l, Vmax = 0.27 pH units/30 s) in cell monolayers using the fluorescent probe biscarboxyethylcarboxy fluorescein. Angiotensin II (10(-7) mol/l) produced a small overall net intracellular alkalinization. Raising intracellular pH via Na+-H+ activation might be one of the ways in which Ang II increases cell growth.